Alport症候群に合併した黄斑円孔の硝子体手術に難渋した1例

A case of Alport syndrome with macular hole that showed difficulty in vitrectomy

要約　目的：Alport症候群はⅣ型コラーゲン異常を原因とした遺伝性疾患であり，進行性遺伝性腎炎や感音性難聴に加えて，再発性角膜びらん，円錐水晶体，斑状網膜などさまざまな眼病変を伴う。筆者らはAlport症候群の網膜所見を長期間にわたり光干渉断層計（OCT）で観察，最終的に黄斑円孔を合併して硝子体手術で人工的後部硝子体剝離作成に難渋した症例を経験したので報告する。

症例：64歳，男性。Alport症候群による難聴と腎不全に対する腎移植歴あり。45歳時に右眼の見づらさが出現し，変視が増悪傾向のため48歳時に精査加療目的に群馬大学医学部附属病院へ紹介され初診となった。

所見：初診時矯正視力は左右ともに1.2であった。両眼黄斑周囲に黄白色点状病変が散在し，OCTでは病変に一致した高輝度病変が内境界膜上にあり，Alport retinopathyと診断した。その後通院中断があったが，両眼の視力低下があり再診した。再診時矯正視力は右0.6，左0.5で，両眼に全層黄斑円孔がみられた。右眼の黄斑円孔に対し硝子体手術を施行したが，人工的後部硝子体剝離の作製を試みるも周辺まで起こらず内境界膜剝離も困難であり，シリコーンオイル注入で手術終了となった。術後OCTで黄斑円孔未閉鎖であったが，円孔径は縮小した。

結論：Alport症候群に合併した黄斑円孔に対する手術適応は，後部硝子体剝離や内境界膜剝離が困難な症例も存在するため，慎重に決定する必要がある。

Abstract　Purpose：Alport syndrome, an inherited disorder caused by type Ⅳ collagen deficiency, is associated with progressive hereditary nephritis, sensorineural hearing loss, and various ocular lesions such as recurrent corneal erosions, lenticonus, and perimacular fleck retinopathy. Here we report a case of Alport syndrome with long-term retinal findings on optical coherence tomography（OCT）and eventually complicated by a macular hole, making vitrectomy to create an artificial posterior vitreous detachment difficult.

Case：A 64-year-old man was referred to our hospital for the examination and treatment of decreased visual acuity in the right eye at 45 years of age. He had hearing loss and a history of renal transplantation due to renal failure caused by Alport syndrome.

Finding and Clinical Course：At his first hospital visit, his best corrected visual acuity（BCVA）was 1.2 in the right eye and 1.2 in the left eye. Funduscopy showed yellow-white spot-like lesions scattered around the macula in both eyes, while OCT showed hyperreflectivity of the inner limiting membrane consistent with the lesions. Because of his history and retinal findings, he was diagnosed with Alport retinopathy. However, he discontinued visiting our hospital. Nineteen years after his initial visit, he returned with bilateral vision loss. The BCVA was 0.6 in the right eye and 0.5 in the left eye, and macular holes were observed in both eyes. A 25-gauge pars plana vitrectomy was performed for a macular hole in the right eye. An artificial posterior vitreous detachment was attempted but did not extend to the periphery, and the surgery was terminated with silicone oil tamponade. Postoperative OCT showed that the macular hole was not closed, but its diameter was reduced.

Conclusion：Vitrectomy indications for macular hole associated with Alport syndrome should be determined carefully due to difficulty performing posterior vitreous detachment and internal limiting membrane peeling.